Development of an optimised non-invasive MRI method to measure renal perfusion in patients with impaired renal function

Arterial Spin Labelling (ASL) is a unique Magnetic Resonance Imaging (MRI) approach for quantifying tissue perfusion non-invasively. More than two decades of technical developments established ASL as a valuable tool in neuroimaging, having more recently began its translation to the clinic. ASL holds great potential for the assessment of kidney disease given that it does not require contrast agents which are typically contraindicated for patients with impaired renal function. However, renal ASL applications remain limited and the technique has yet to be incorporated into clinical practice. The sensitivity of ASL to patient movement, which severely corrupts the renal perfusion estimates, is arguably one of the greatest factors hindering a wide adoption of this technique. This thesis begins with an overview of the main concepts addressed in this work (kidney physiology, MRI and ASL) and a thorough literature review of previous renal ASL work. The problem of patient movement is then addressed at all levels of the ASL framework by combining a motion-insensitive ASL acquisition scheme with a specifically tailored image processing pipeline. The feasibility of this technique to provide repeatable renal perfusion measurements is demonstrated in the first paediatric cohort with impaired renal function to undergo renal ASL. Finally, the critical findings of this thesis are summarised and prospective future research directions are outlined